1. Field of the Invention
The disclosed embodiments of the invention pertain to the removal of contaminated objects from soil, and, more particularly, to a system and method for excavating contaminated soil surrounding a piling, removing the piling and the contaminated soil, and filling the resulting hole with uncontaminated material.
2. Description of the Related Art
Pilings and similar support structures, such as fence posts, telephone poles, and light poles, are frequently treated with a preservative to resist corrosion and decay when mounted in the soil. In the past, creosote has been one preservative used to protect the wood. It has been discovered that creosote and other preservatives can be damaging to the environment and harmful to nearby life.
More particularly, creosote can seep into the soil surrounding the posts and pilings and pollute the soil, causing damage to plants growing nearby and endangering animal and human life as well as aquatic life. For example, barnacles, muscles, and similar aquatic life can attach themselves to creosote-treated pilings, becoming themselves contaminated. Marine life feeding on this contaminated material become contaminated and will in turn spread the contamination. Hence, there is a need to replace aging posts and pilings with environmentally safe substitutes.
Removing old posts and pilings, however, presents a number of challenges, not the least of which is causing further environmental damage in the removal process, and increased danger to nearby aquatic and animal life. For example, disturbing the contaminated soil and material attached to a piling while attempting to remove the piling will spread the contamination beyond the immediate area. Moreover, older pilings that have rotted tend to break apart when pulled upward, further spreading the contamination and making it more difficult to remove the remaining stub.
A number of devices have been proposed for removing pilings and the like. However, none of these address or solve the problem of containing and removing contaminants along with the piling. For example, U.S. Pat. No. 3,379,265 directed to a pile extractor and setter discloses lowering a casing over a piling and injecting liquid, such as water, or a gas, such as air, through nozzles on the casing to assist in driving the casing into the soil so that teeth on the casing will dig into the earth or sea bottom. In this device, excavated mud is expelled through mud slots in the casing into the surrounding water, which would further spread contaminants associated with the piling and the surrounding soil.
As another example, U.S. Pat. No. Re. 28,945 discloses an apparatus for excavating a tailing pond where high pressure liquid is jetted from inside a caisson to the soil on the outside of the caisson to create a pulping zone surrounding the caisson. The slurry formed in the pulping zone flows through portals in the bottom of the caisson into a slurry sump where it is pumped out to excavate the soil. Here, the outwardly-oriented water jets create a cloud of slurry outside the caisson that spreads throughout the water, extending the zone of contamination far beyond the immediate area.
Yet another example is an apparatus for removing piles disclosed in U.S. Pat. No. 1,644,560, wherein a plurality of pipes are lowered around the outside of a piling and high pressure water is forced out the bottom of the pipes to excavate the soil around the piling. In this device, the jetted water and loosened soil are not contained, resulting in a spreading of any contamination in the soil.
In a related device disclosed in U.S. Pat. No. 4,644,715, a soil-excavating sleeve having teeth on the bottom, interior doors, and flaps on the sides of the sleep, is rotated into the ground around a utility pole for half its length and left in place. The soil is excavated by the action of the doors or flaps forcing the soil out of the cylinder. The excavated annulus of soil is then filled with hardenable material and the sleeve is left in place as a re-enforcement to the utility pole. Here, the pole and the sleeve are left in the ground where the contamination can continue to spread, and not all of the contaminated soil is removed.
Hence, there is a need for a device that can excavate the soil surrounding a contaminated post or piling and remove the soil and the post or piling without endangering the environment and nearby life.
The present invention is directed to a system and apparatus for excavating a contaminated object, such as a post or piling. In accordance with one embodiment of the invention, an excavation device is provided for removing an object from the soil, the device having a casing sized to be slidably received over the object and an excavation system associated with the casing for removing soil from around the object, the system using pressurized air to force soil to rise inside the casing and to remove the rising soil from the inside of the casing. Ideally, a mixture of pressurized air and liquid is used in environments where the soil is not under water.
In accordance with another aspect of the foregoing embodiment, the excavation system includes a plurality of nozzles associated with the casing and is configured to direct a stream of pressurized fluid, ideally comprising high-pressure air, towards the object and the soil to remove material from the object and excavate the soil; and a device for removing the excavated soil from within the casing. The removing device can comprise a suction hose or a filter for capturing the removed material and excavated soil.
In accordance with a further aspect of the foregoing embodiment, a closure mechanism is provided at one end of the casing used under water to enclose the object within the casing as the object is removed.
In accordance with still yet another aspect of the foregoing embodiment, ballast is provided to be attached to the casing for giving additional weight to the casing and to be used in replacing the removed soil and the void left by the removed object.
In accordance with another embodiment of the invention, a system is provided for removing a post from soil that includes a casing sized to be slidably received over the piling; and an excavating system for excavating soil from around the piling using pressurized air to force soil to rise inside the casing and to remove the soil from inside the casing; a device for forcing the casing into the soil; and a device for pulling the post from the soil.
In accordance with another embodiment of the invention, a system is provided for removing a piling from soil under water, the system including a casing having an interior sized to be slidably received over the piling; a plurality of air nozzles mounted near a first end of the casing and oriented to direct pressurized air at least towards the soil and also towards the piling to loosen soil from around the piling and to remove material from the piling, and to force the soil and removed material to rise to the surface of the water; and a device for capturing and removing the soil and material from the water in the interior of the casing.
In accordance with another embodiment of the invention, a method is provided for removing a post from soil, the method including placing a casing around the post; driving a casing into the soil; excavating soil from around the post using pressurized air to force the soil to rise inside the casing and removing the soil from inside the casing; and removing the post.
In accordance with still yet another embodiment of the invention, a method is provided for removing a piling from soil under water, the method including placing a casing around the piling; driving the casing into the soil; directing at least pressurized air through nozzles on the casing to the soil around the piling to loosen the soil and force the soil to rise upward inside the interior of the casing; removing the rising soil from the interior of the casing; and removing the post. Ideally, the air nozzles are also directed to the piling to remove contaminated debris from the piling, and the debris is forced to rise upward inside the casing.
In accordance with another aspect of the foregoing embodiment, the method further includes enclosing the bottom of the casing when the piling is removed to ensure all of the piling materials are removed from the water. Ideally, a fill material is injected in the remaining void to replace the removed soil and the piling.
As will be readily appreciated from the foregoing, the advantages of the present invention are that it completely contains the contaminated material as it is being excavated from around the piling and from off of the piling, including the soil, barnacles, and the like. This material is then forced to rise upward within the casing by the rising air from the pressurized nozzles. Because the casing completely surrounds the piling, and the pressurized air is injected within the casing and directed at the soil and the piling, the removed material and the excavated soil remain within the casing instead of spreading the contamination outside the immediate area. The optional doors on the bottom of the casing enclose the pole or piling as it is being lifted to ensure that all of the debris and other material associated with the contaminated object are removed from the water without spreading the contamination. The air nozzles can also be used to inject a fill material into the area where the object was removed to replace the excavated soil. Optional ballast to give the casing weight can sand that is later used to replace the soil and fill the void left by the removed object. It can be appreciated that the present invention can be modified for use in land operations where a mixture of air and water are injected inside the casing to excavate the soil surrounding the object.